I had the chance to meet and debate with Peter Brimelow, a senior editor of Forbes, this week at the Claremont Institute. I can report that he is utterly charming, unusually persuasive, often thought-provoking — and utterly wrong.

Peter has written a new book, Alien Nation (Random House, 327 pp., 24.00) in which he argues that immigration has reached potentially dangerous and disruptive levels in this country, that today's immigrants are less educated and more likely to go on welfare or be involved in crime than previous generations, and that it's time for a moratorium — no net immigrants in a given year — on immigration.

Well, you have to say Peter Brimelow is a quick study. For most immigrant families, it takes about a generation to come to the conclusion that there are plenty of people in the United States and it's time to pull up the drawbridge. Brimelow, who was born in England and lived in Canada before becoming a U.S. citizen, has managed it in about 15 years.

Not that he doesn't raise some concerns worth worrying about or remind us that some in the pro-immigration crowd have purveyed myths. It's useful to be reminded, for example, that the United States hasn't experienced a steady stream of immigration throughout its history, but that immigration has come in waves punctuated by lulls.

It is also true that today's immigrants are moving into a mature welfare state in which government assistance is aggressively marketed rather than into a society that encourages newcomers to make it on their own. And today's dominant political culture does encourage some variant of a twisted "multiculturalism" rather than promote "Americanization" as was true in previous generations. And the 1965 immigration act, as amended in 1986, creates a system in which government promotes and subsidizes certain immigrants rather than letting free choice and market transactions determine the level of immigration.

But Brimelow also tries to make a case that the recent wave of immigration has not been a benefit to the native-born population. Although he sounds self-assured, he doesn't make the case. He doesn't deal with the fact, for example, that about a third of the engineers in the most advanced American computer companies are immigrants.

He doesn't sufficiently explain the fact that if somebody is willing to pay somebody to do work (often ignoring that person's legal status) the person who does the hiring must feel he's getting a benefit or he wouldn't fork over the money. How do you get from a network of mutually beneficial transactions to a result that is supposedly deleterious to society as a whole?

Another recent book explains some of the factors Brimelow ignores or glosses over. The Case for Free Trade and Open Immigration , published by the Future of Freedom Foundation (11359 Random Hills Rd. Fairfax, Va. 22030) includes essays from James Bovard, Jacob Hornberger, Professor Richard M. Ebeling, Sheldon Richman, Ron Unz, and others, that explain the benefits of free trade and the free movement of peoples.

The contributors explain that free trade and open immigration are closely related, two aspects of what constitutes a free society, two natural rights that government has no just reason to inhibit, and transactions that have promoted progress and prosperity to the extent that they have been permitted.

The authors also note that talk of limiting immigration betrays an inherently collectivist attitude toward human endeavors. If we don't think bureaucrats in Washington should be allowed to prescribe the precise design of filters on the emission systems of our cars or the exact formula of gasoline, why should they be allowed to dictate the precise composition of our neighborhoods?

The case that immigrants contribute to an erosion of family values and the work ethic is somewhat underwhelming. As The Manhattan Institute and Pacific Research Institute have pointed out in their recent "Index of Leading Immigration Indicators," the number of immigrants these days is smaller as a proportion of the total population than in some previous decades. Immigrants are more likely than natives to live in families (76 percent to 70 percent), to be married (60 percent to 55 per cent), and to be of working age (71 percent to 56 percent. They are less likely to work for the government (10 percent to 16 percent).

While immigrants taken as a whole are more likely to receive welfare than natives, that figure is skewed by the high rates of welfare use among elderly immigrants and refugees. Non-refugee immigrants of working age are less likely to be on welfare than are native-born Americans. And while some immigrants do get stuck in the welfare system, most move on and are likely to earn a higher income than natives by the time they've been here 10 years.

The proponents and opponents of immigration can trade such statistics and argue about their significance until the cows come home (or the nation decays). But the key questions can't be answered by statistics: What kind of nation is this now, and what kind of nation does it aspire to be in the near future?

Has this country reached some sort of peak in terms of being able to grow and provide opportunity? Is it close to exhaustion, perhaps beginning a downward slide? Is it so crowded, so strained, so stressed, that new people become a drain rather than an opportunity? If you think so, perhaps you have a right to think about limiting future immigration.

This country does have problems — a bloated and demoralizing welfare system, a public education system that delivers very little for the money, too many taxes and regulations, too much government, a flirtation with a phony and divisive brand of multiculturalism —but most of them are homegrown, not the result of immigration. Limiting immigration won't solve a single one of these problems, and focusing on immigration as a source of problems rather than another symptom could divert our attention from dealing with our real problems.